I don't see the poisoning plan having much of a chance of success. How to get the Jem'Hadar to take Federation White as opposed to their own? Leave it lying attractively on some rock at a planet the Jem'Hadar are in the process of conquering?
Even if the Feds through some outlandish plan managed to get the poison spread to a couple of million Jem'Hadar at the same time, and they all died, what good would that do? The Jem'Hadar don't live particularly long anyway. There would simply be more produced, now even more firmly controlled by the people who dispense the White ("Not only do you need this stuff to live, you need to follow our dispensing ceremony to the hilt or the enemy will poison you").
Bribing the Jem'Hadar with perfectly safe and good White sounds like a more workable plan, to be used in whatever scale the situation necessitates. But supposedly the Founders or the Vorta have some means of keeping the Jem'Hadar from exploiting Cardassian or captured Federation replicators for self-producing White; these same means would kick in if rebel Jem'Hadar tried to accept these bribes (perhaps much as in "To the Death").
Timo Saloniemi